Ignition device.



UNITED STATES PATENT ornroil.

BURNS DICK, OF ST. LOUIS, MISSOURI, ASSIGNOR TO WAGNER ELECTRICMAN'UFAG- TUBING COMPANY, OF ST. LOUIS, MISSOURI, A CORPORATION OFMISSOURI.

IGNITION DEVICE.

Specification of Letters Patent.

Patented Deo. 4, 1917.

Application filed July 19, 1915. Serial No. 40,601.

To all whom it may concern:

Be it known that 1, Bonus DICK, a subject of the Kin of England,residing at the city of St. Louls, State of Missouri, United States ofAmerica, have invented a certain new and useful Ignition. Device, ofwhich the following is such a full, clear, and exact description as willenable any one skilled in the art to which it appertains to make and usethe same,"reference being had to the accompanying drawings, forming partof this specification.

My invention relates to ignition apparatus for lnternal combustionengines, and more particularly to improved means for automaticallycausing the maximum explosion pressure to occur at an efficient point ofthe crank revolution under all load conditions.

The timing of the ignition spark and therefore the time of occurrence ofthe maximum explosion pressure has heretofore, so

. far as I am a-Ware,'been placed. either under the direct control ofthe operator or driver, or has been made dependent Onthe speed of theengine. When placed under the dirent control of the driver, the timingof the spark is usually accomplished by 'IDOVlIlg a lever operativelyconnected with a part of the timer and arran ed to move said part withrelation to anot er and generally sta 'tionary portion of the sameapparatus. When made dependent upon the speed, the

movable part of the timmg apparatus is placed under the control of someform or ccntrifugal governor driven by the engine. In the'apparatusherein described, I provide a plurality of spar-h gaps, locate them atdifferent distances from the main body of the compression chamber, andso constitute the electrical circuits within which said s ark-gaps arelocated that the one nearest the mam body of the compression chamberwill be efi'ective at low cylinder compressions While that farthest awayfrom said main body. will be effective at high cylinder compressions.This arrangement yields the'de sired results by virtue of the facts thatat a irer. speed the torque varies with the cyl indcr compression, thatthe resistance of a spark gap increases with the compression, and thatthe rate of flame propagation decreases as the distance of the effectivespark' gap from the main body of the compression chamber increases.

In the accompanying drawings, Figure 1 diagrammatically illustrates anembodiment of my invention. Fig. 2 shows a modification. Fig. 3illustrates one form of a spark plug provided with a plurality of sparkgaps in accordance with the invcntiom Referring to Fig. l, thecompression and explosion chamber 2 otthe cylinder 16 is provided with apocket or ignition chamber 3 within which are located spark terminalsforming two spark gaps 4 and 5, of which .4 is placed in close proximityto the main body of the c-:..=mpression chamber 2, while 5 is locatedback in the pocket 3. Both of these spark gaps are in circuit with thehigh tension winding 7 of an ignition coil, the primary or low tensionwinding 8 of which is connected in series with the battery 9 and theinterrupter 10. The interrupter is controlled by the spring 12 and isactuated by the cam 11, driven by the engine, to break the primarycircuit in the usual way at the contacts 13, 14. The terminals formingthe spark gap 4:, whiph is placed near the main body of the explosionchamber 2, are directly -connected to the high tension winding 7 of thespark coil, but the terminals forming Jtlie spark gap 5, which isremoved frorlrvthe mam body of the explosion chamber, are connected tothe high tension winding 7 through. air-gap 6 placed outside of thecylinder 16. The magnitudes of thespark gap 5, and of the air-gap 6, andthat of the spark gap 4', are so chosen that when all of them aresubject to atmospheric pressure, 01' when galps 5 and 4. are under theinfluence of low cy inder compressions, the spark, followinc idealdriver is-supp'osed to achieve by mamis, with increasing mechanicalcompression within the cylinder, and for reasons hereinafter pointedout, there may be a time when sphrks will be produced at both sparkgaps, but, after the mechanical compression produced within the chamber2 has further in: creased, the spark gap 1 will become dead and thespark gap 5 alone will be effective. When spark gap 1 is effective, therate of flame propagation will be rapid and the explosion pressure willoccur with n a very short time after the separation of the contacts 13and 14;. When the mechanical compression has increased to an extentsuflicient to make the spark gap 4 ineffective and to render spark gap 5active, the rate of flame propagation will be considerably slower, dueto the'fact that spark gap '5 is located. deep within the pocket 3 andtherefore at some distance from the main body of the chamber 2. The rateof flame propagation being slower, a longer time interval will elapsebetween the separation of the contacts- 13, 14' and the production of-the maximum explosion pres mre. These conditions correspond j to aretardation of the spark with increasing torque, and therefore,achieveautomatically the results which an ual' manipulation of: thespark timing lever. It has beenfoundthat the resistance of a given sparkgap increases wlth the pressure 7 of the medium withinwhich a islocated, and it-is this fact that I make'use of .to 'make the spark gap4 ineffective and to render the] spark gap 5 effective at the highercylinder To this end all of the 1mcompressions. v 'pedance' of thecircuit wlth ni which spark gap dis located is concentratedin said sparkgap itself,- whereas the impedance of the other spark gap circuit isdivided between the spark gap 5. and the air-gap 6. Under theseconditions an increasein'cylinder compressi'on will increase all of theimpedance inthe circuit-of the spark gap 4:, but will.

only increase a part'of the impedance 1n the circuit of the spark'gap5,since a por-,..

tien of that total impedance, re sented by' the. resistance of theair-gap is located outside of, the cylinder and is only sub ect to theatmospheric pressure, which 18 practically "constant.-

Speaking generally, an impedance is ex pressed'as r z- (I -F whererstands for the ohmic resistance and w for the react'ance, which maybe"ositive' (inductance) or neg-atiye (cap impendance, therefore,fility'cpn ist pure 1 ohmic resistance, or of pure 1n uctan-ce or ofpure capacity, but the hamlet r cases are not met within practice, forso'm ohm1c resistance is "almost always present, In the modificationshown in Fig. 2, the external air-ga 6, within the circuit of spark gap5 whic is located at some distance from the main body of the explosionchamber, is 'replaced b a positive reactance or inductance clampedbetween it and a cap The sul'ator 18'supports'the 'rod'21 in'ca sed inan insulator 20 which fits loosely into a cen-' tral opening through theinsulator'18, passes through the insulatingv washer 25 and reaches intothe insulating washer, 26. projection'of the insulator 20 rests on thelower part of the insulator 18.1-All upward movement of the rod 21 isrevented; by a distance piece 23 and a' was er 22"clajmped under thehead of the rod 21. A"ni1t"27,

which screws onto the upper part of the rod 21, presses the washer 22,the distance piece 23, the insulator 9-0, and the insulating Washers 25and 26 against the'insulator holding all of these together with the foe21 in a fixed' position relatively to the insulator 18. Formedintegralwiththe metal washer 22 is a sparking electrode 24, which formsthe spark gap 4 together with the in nor Wall of the spark plug housing17. l A

thin metal c linder 31 is located between the insulators 1 and 20. Atits lower end it carries the sparking electrode 32 which I -passesthrough suitable opening provided new insulator 20 and forms the sparkgap 5 together with the inner wall of the spark plug housing 17.Connected to the upper end of the conductin tube 31 is the sparkgapelectrode =33. whic passes out of the-in sulati'ng b0dy18 through asuitable opening therein and reaches' u wardgifitoan opening '6 providedin the'lnsuleting washer 25.

Clampe d between the in'siiliihing washers 25.-.

and 26 is a conducting .late 30 provided with a spark gap-jeledt'ro ereaching down-i washer 25. Clamped between the nut 27 and the thumb nut29 is a'terf ninal.28which connects with the spark electrode 24;,

ward into the opening 6 of-the insulating" through the nuts 27, 29, therod 21, and the washer 221 The, central openings in the insulators 18,and 20 are sealed with a suitable compound, so as to prevent the escape.of gases from the cogr'hustmn chamber 2; The

terminals 28 and- 3 0 are both connected to 3 one end of the secondary7. of the ignition coil, the othepiend' of which is grounded. Theprimary 0 this coil 8 is in circuit with the battery 9 and themechanically-operated} interrupter contacts 13, 14. It is seen that"this spark plug providestwo spark gaps; lo-

cated inoperative relation with regard to neeaze the ignition chamberThe longer of these spark gaps is located at l, in close. proximity tothe main body of the cmnbnstion chamber 2, wlm'reas the smaller gap 53is located deep within the pocket 3 formed by the housing'oi': the sparkplug. The larger spark 'gap l directly connected to the .oncary 7,whereas the smaller spark 5 is separated from the secondary T by theauxiliary gap located in the opening (3 of the insulating; washer "lsecond. gap is exposed to atmospheric pres-sure only, whereas the sparkgaps 4: and 5 are subject to whatever pressure may exist within thecombustion chamber 2.

It will be understood that more than two spark gaps may be provided forwithin each cylinder. Such spark gaps suouid be located at differentdistances from the main body of the explosion chamber, and the totalimpedances of the various spark gap circuits and the portions of saidimpedances which are located outside of the cylinder, should be sochosen that at low fuel pressures ignition s' arks are. )roduced at asnark a") .ilaccd l r; l

near the main body of the explosion chain her, while at increasing fuelpressures said ignition sparks are produced at spark gaps locatedfarther and farther away from the anain body of the explosion chamber.

Having. fully described my invention, What I claim as new and desire tosecure by Letters-Patlent of the United States is:

1. In an internal combustion engine, the combination of electrodesforming a. plurality of stationary ignition spark gaps atdifferentpositions, and means preventing the production of an ignitionspark at one of said gaps at the higher fuel pressures.

2. In an internal combustion engine, the combination of an explosionchamber, elec trodes forming a plurality of stationary ignition sparkgaps, and means for causing the ignition spark to be produced atone ofsaid gaps at low fuel pressures in the explosion chamber and at adifferent gap at the higher fuel pressures in said chamber.

3. In an internal combustion engine, the

combination of an explosion chamber, electrodes forming two stationaryspur-z gaps for igniting the fuel, said gaps being at difiercntpositions and of different lengths, and an impedance unaffected bypressure in the explosion chamber and in circuit with the electrodesforming one of the spark gaps.

t. In an internal combustion engine, the

combination of an explosion chamber, elec-.

trodes forming two ignition spark gaps, and. an impedance unaffected bypressure in the explosion chamber and in circuit with the electrodesformingone of said gaps.

In an internal combustion engine, the combination of an explosionchamber, elecum forming two ignition spark gaps 0peratwcly located withrespect to the explocombination of an explosion chamber, an

auxiliary chamber communicating therewith, electrodes forming twoignition spark gaps, one of the said gaps being Within the auxiliarychamber and farther from the explosion chamber than the other, a sourceof ignition 'voltage connected to the said elec trodes, and meanspreventing the production of an ignition spark at one spark gap when thecompression of the fuel is high.

7. In an internal combustion engine, the combination of an explosionchamber, an auxiliary chamber communicatingtherewith, electrodes formingtwo ignition spark gaps, one of the said gaps bein "within the auxiliarychamber and farther roin the explosion chamber than the other, a sourceof ignition voltage connected to the said electrodes, and means forcausing the ignition spark to be produced at one of said gaps at lowfuel pressures in the explosion chamber and at a different gap at thehigher fuel pressures in said chamber.

8. In aninternal combustion engine, the combination of an explosionchamber, an auxiliary chamber in communication therewith, electrodesforming two spark ps for. igniting the fuel, said gaps bein 0 differentlength, and the shorter gap lieing situated within the auxiliary chamberand farther from the explosion chamber than the other, and an impedanceunafl'ected by pressure in the explosion chamber and in circuit with theelectrodes forming the shorter spark gap.

the

-with, electrodes forming two spark gaps for igniting the fuel, saidgaps being ofdifi'crent length, the shorter gs. being situatedwithin theauxiliary cliamber and farther from the ex losion chamber than theother, a. source 0 ignition voltage connected to the said electrodes,the electrodes forming one spark gap, being connected to the said'sourcein parallel circuitwith the electrodes forming the other spark gap, and

an impedance unaffected by pressure in the explosionchamber and inseries with the electrodes forming the shorter gap.

10. In an internalcombustion engine, the combination of an explosionchamber, an auxiliary chamber in communication there: with, electrodesforming two spark gaps for igniting the fuel, said gaps being ofdifi'erres - said electrodes, the electrodes forming one 0 the twosubscribing witnesses.

spark gap being connected to-the Sit-1d source ent length, the shorterga being situated shorter gap and positioned outside the fuel 10 withinthe auxiliary chain er and farther chambers. v from theeiiplosionchamber than the other, In testimony whereof, Ihave hereunto set asource of ignition voltage connected to the to hand and aflixed my sealin the: presenoe BURNS DICK. [1451 in parallel circuit with theeieet-rodesfor m Kitnesses: ing the other spark gap, and a third sparkCARL C. ADAMS,

gap in series with the electrodes forming the HAReY HENzE.

